Abstract: This study is to investigate the effect of recombinant human interferon alpha 2b against broad-spectrum respiratory viruses in vitro. At the cellular level, the effect of the recombinant human interferon alpha 2b on influenza A virus was detected using real-time fluorescence quantitative RT-PCR. The effects of the recombinant human interferon alpha 2b on influenza B virus, parainfluenza virus, respiratory syncytial virus(RSV)and coronavirus were detected using cytopathic effect(CPE)method. In this study, the therapeutic index of recombinant human interferon alpha 2b anti-HPIV was 1476.63, the therapeutic index of recombinant human interferon alpha 2b anti-RSV was 141.37, the therapeutic index of recombinant human interferon alpha 2b anti-coronavirus was more than 2820.76, and the antiviral effect of recombinant human interferon alpha 2b was better than ribavirin(RBV). Recombinant human interferon alpha 2b has a stronger inhibitory effect on different influenza A virus RNA than drug control. The therapeutic index of recombinant human interferon alpha 2b anti-influenza B virus was 2.74, with modest effect. Recombinant human interferon alpha 2b in vitro has broad spectrum antiviral activities, low toxicity and high therapeutic index. Recombinant human interferon alpha 2b is expected to become the efficient medicine in clinical against respiratory viruses, as well as provide better services for prevention and treatment of respiratory viruses' infections.